use js::class::Trace;
use js::prelude::{Coerced, Opt};
use js::{Array, Ctx, Exception, FromJs, JsLifetime, Result, Value};

use crate::dbs::Variables;
use crate::expr::Expr;
use crate::syn;
use crate::val::Value as SurValue;

#[js::class]
#[derive(Trace, Clone, JsLifetime)]
pub(crate) struct Query {
	#[qjs(skip_trace)]
	pub(crate) query: Expr,
	#[qjs(skip_trace)]
	pub(crate) vars: Option<Variables>,
}

#[derive(Default, Clone)]
pub(crate) struct QueryVariables(pub(crate) Variables);

impl QueryVariables {
	pub fn new() -> Self {
		QueryVariables(Variables::new())
	}

	pub fn from_value<'js>(ctx: &Ctx<'js>, val: Value<'js>) -> Result<Self> {
		static INVALID_ERROR: &str = "Query argument was neither sequence<[String,SurValue]> or record<ByteString, SurValue>";
		let mut res = Self::new();

		// TODO Set and Map,
		if let Some(array) = val.as_array() {
			// a sequence<sequence<String>>;
			for v in array.iter::<Array>() {
				let v = match v {
					Ok(x) => x,
					Err(e) => {
						if e.is_from_js() {
							return Err(Exception::throw_type(ctx, INVALID_ERROR));
						}
						return Err(e);
					}
				};
				let key = match v.get::<Coerced<String>>(0) {
					Ok(x) => x,
					Err(e) => {
						if e.is_from_js() {
							return Err(Exception::throw_type(ctx, INVALID_ERROR));
						}
						return Err(e);
					}
				};
				let value = match v.get::<SurValue>(1) {
					Ok(x) => x,
					Err(e) => {
						if e.is_from_js() {
							return Err(Exception::throw_type(ctx, INVALID_ERROR));
						}
						return Err(e);
					}
				};
				res.0.insert(key.0, value);
			}
		} else if let Some(obj) = val.as_object() {
			// a record<String,String>;
			for prop in obj.props::<String, SurValue>() {
				let (key, value) = match prop {
					Ok(x) => x,
					Err(e) => {
						if e.is_from_js() {
							return Err(Exception::throw_type(ctx, INVALID_ERROR));
						}
						return Err(e);
					}
				};
				res.0.insert(key, value);
			}
		} else {
			return Err(Exception::throw_type(ctx, INVALID_ERROR));
		}

		Ok(res)
	}
}

impl<'js> FromJs<'js> for QueryVariables {
	fn from_js(ctx: &Ctx<'js>, value: Value<'js>) -> Result<Self> {
		QueryVariables::from_value(ctx, value)
	}
}

#[js::methods]
impl Query {
	#[qjs(constructor)]
	pub fn new(ctx: Ctx<'_>, text: String, variables: Opt<QueryVariables>) -> Result<Self> {
		let query = syn::expr(&text)
			.map_err(|e| {
				let error_text = format!("{}", e);
				Exception::throw_type(&ctx, &error_text)
			})?
			.into();
		let vars = variables.into_inner().map(|x| x.0);
		Ok(Query {
			query,
			vars,
		})
	}

	#[qjs(rename = "toString")]
	pub fn js_to_string(&self) -> String {
		format!("{}", self.query)
	}

	pub fn bind(&mut self, key: Coerced<String>, value: SurValue) {
		self.vars.get_or_insert_with(Variables::new).insert(key.0, value);
	}
}
